What does indignation mean?

Indignation is a form of anger. It's an angry reaction to something that is unfair, mean, or unjust. It's also called "righteous anger."

Have you ever been yelled at for something you didn't do? What did you feel? You got angry, right? How did you respond? It was with indignation!

Or imagine this: After a lot of research, you developed a brilliant idea for the science fair and told a bunch of people about it. Unfortunately, someone copied your idea — and won first place! How do you feel? Indignant!